org.hibernate.bytecode.spi.InstrumentedClassLoader Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.bytecode.spi;
import java.io.InputStream;
/**
* A specialized classloader which performs bytecode enhancement on class
* definitions as they are loaded into the classloader scope.
*
* @author Emmanuel Bernard
* @author Steve Ebersole
*/
public class InstrumentedClassLoader extends ClassLoader {
private ClassTransformer classTransformer;
public InstrumentedClassLoader(ClassLoader parent, ClassTransformer classTransformer) {
super( parent );
this.classTransformer = classTransformer;
}
public Class loadClass(String name) throws ClassNotFoundException {
if ( name.startsWith( "java." ) || classTransformer == null ) {
return getParent().loadClass( name );
}
Class c = findLoadedClass( name );
if ( c != null ) {
return c;
}
InputStream is = this.getResourceAsStream( name.replace( '.', '/' ) + ".class" );
if ( is == null ) {
throw new ClassNotFoundException( name + " not found" );
}
try {
byte[] originalBytecode = ByteCodeHelper.readByteCode( is );
byte[] transformedBytecode = classTransformer.transform( getParent(), name, null, null, originalBytecode );
if ( originalBytecode == transformedBytecode ) {
// no transformations took place, so handle it as we would a
// non-instrumented class
return getParent().loadClass( name );
}
else {
return defineClass( name, transformedBytecode, 0, transformedBytecode.length );
}
}
catch( Throwable t ) {
throw new ClassNotFoundException( name + " not found", t );
}
}
}